No evidence of myocardial restoration following transplantation of mononuclear bone marrow cells in coronary bypass grafting surgery patients based upon cardiac spect and 18F-PET

Background : We tested the hypothesis that intramyocardial injection of mononuclear bone marrow cells combined with coronary artery bypass grafting (CABG) surgery improves tissue viability or function in infarct regions with non-viable myocardium as assessed by nuclear imaging techniques. Methods : Thus far, seven patients (60 ± 10 [SD] years) undergoing elective CABG surgery after a myocardial infarction were included in this study. Prior to sternotomy, bone marrow was harvested by sternal puncture. Mononuclear bone marrow cells were isolated by gradient centrifugation and resuspended in 2 ml volume of Hank's buffered salt solution. At the end of CABG surgery 10 injections of 0.2 ml each were applied to the core area and border zones of the infarct. Global and regional perfusion and viability were evaluated by ECG-gated 99m Tc-tetrofosmin myocardial single-photon emission computed tomograph (SPECT) imaging and 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) in all study patients < 6 days before and 3 months after the intervention. Results : Non-viable segments indicating transmural defects were identified in five patients. Two patients were found to have non-transmural defects before surgery. Concomitant surgical revascularisation and bone marrow cell injection was performed in all patients without major complications. The median total injected mononuclear cell number was 7.0 x 107 (range: 0.8-20.4). At 3 months 99m Tc-tetrofosmin SPECT and 18 F-FDG-PET scanning showed in 5 patients (transmural defect n = 4; non-transmural defect n = 1) no change in myocardial viability and in two patients (transmural defect n = 1, non-transmural defect n = 1) enhanced myocardial viability by 75%. Overall, global and regional LV ejection fraction was not significantly increased after surgery compared with the preoperative value. Conclusion : In CABG surgery patients with non-viable segments the concurrent use of intramyocardial cell transfer did not show any clear improvement in tissue viability or function by means of non-invasive bioimaging techniques.